Aluminized explosives



1 tainers.

Unite ttes a ALUNIINIZED EXPLOSIVES John W. Dawson, Philadelphia, Pa., and Frank H. Westheimer, Chicago, 11]., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy No Drawing. Filed May 6, 1946, Ser. No. 667,732

3 Claims. (Cl. 52-6) This invention relates to aluminized explosives, i.e., explosives which contain powdered aluminum as one of their principal components, such as those known in the art as Torpex and Minol; the invention pertains particularly to aluminized explosives which are conditioned to pour into a container without spewing and to generate only an inappreciable quantity of gas in the enclosed container.

An obvious disadvantage to aluminized explosives which have a tendency to spew is the accompanying difficulty with which such explosives are loaded into con- The marked tendency for these aluminized explosives to generate gas, even when in the solid form, is another disadvantage of previously used aluminized explosives since the pressure thus generated inside the container may grow to the point where it is capable of collapsing the booster cavity, or some similar weak structure within the container assembly. Moreover, in the case of Torpex some of the gas generated is hydrogen and thus represents a fire hazard. Presumably, this gas is generated by the action of moisture on aluminum or other constituents of the explosive mixture.

It is known that aluminized explosives may be desensitized with wax and this practice has been almost universally adopted by the ordnance profession. The wax, however, has a tendency to exude at moderately high storage temperatures, for example 60 degrees C., such as might be found in the holds of ships or in the tropics.

We have found that the tendency of aluminized explosive compositions to generate gas is greatly reduced or eliminated by the addition thereto of a hydrophilic or desiccating agent, such as magnesium nitrate, calcium chloride, or magnesium perchlorate.

The mechanism by which the hydrophilic agent inhibits the generation of gas is believed to be a hydration reaction whereby the moisture contained in the explosive mixture is chemically combined with the hydrophilic agent to form a hydrate thereof, thus rendering the Water incapable of reacting with the aluminum to form a gas. As a further consequence of this gas-inhibiting reaction, it has been found that aluminized explosives which have been desensitized with wax, exhibit a considerably smaller tendency to exude even at moderately high storage temperatures. It is believed that this advantage results from the fact that the hydrophilic agent reduces the gas evolved from the explosive, and that when little or no gas is thus generated the tendency for the wax to exude is reduced.

In the following examples of aluminized explosives made in accordance with the present invention, it will be understood that the term RDX is a short designation for cyclotrimethylenetrinitramine (also known as cyclonite), and that the term TNT is the short designation for trinitrotoluene.

Calcium chloride (anhydrous, finely divided)-.. 0.5

2 Example 2:

Ammonium nitrate 40 TNT 40 Aluminum (finely divided) l8 Magnesium nitrate (anhydrous or monohydrate,

finely divided) I 4 Example 3:

TNT 80 Aluminum (finely divided) 20 Calcium chloride (anhydrous, finely divided) 0.5 Example 4:

RDX 42 TNT 40 Aluminum (finely divided) 18 Wax 4 Nitrocellulose 0.7 Lecithin 0.2

Calcium chloride (anhydrous, finely divided) 0.5

In all of the above examples, the explosive composition exhibited a greatly reduced tendency to spew and to generate gas both while the pouring operation was being conducted and also after the explosive had been introduced into a projectile or mine body. In the case of Example 4 in which wax was used as a desensitizing agent, little or no wax was seen to exude from the explosive case. It should be noted that in all of the above examples there was no perceptible change in sensitivity of explosive caused by the addition of the hydrophilic or desiccating agent.

Although we prefer to employ magnesium nitrate, calcium cloride or magnesium perchlorate as the desiccating agents with our improved aluminized explosives, and have limited the examples herein to those agents, we do not intend so to limit our invention, for it is obvious that other desiccating or hydrophilic agents may be effectively used in this manner. Moreover, we do not intend to be limited closely to the preferred proportions in which our desiccants have been used, as set forth in the examples, since theeifectiveness of the desiccant to perform its appointed function is manifestly dependent upon the quantity used and may be varied widely according to the preference of the individual employing the invention.

We claim:

1. A cast composition consisting essentially of at least 18 parts by weight of powdered aluminum, a minor portion varyingfrom /2 to 4 parts by weight of a desiccant selected from the group consisting of anhydrous calcium chloride, magnesium nitrate, and magnesium perchlorate,

and at least parts by weight of an explosive containing at least 40 parts by weight of trinitrotoluene.

2. A cast composition consisting essentially of about 20 parts by weight of powdered aluminum, about /2 part by weight of powdered anhydrous calcium chloride, and about 82 parts by weight of an explosive containing approximately 42 parts cyclonite and 40 parts of trinitrotoluene.

3. A cast composition consisting essentially of about 20 parts by weight of powdered aluminum, about /2 part by weight of powdered anhydrous calcium chloride, and about 80 parts by weight of an explosive containing approximately 40 parts of ammonium nitrate and 40 parts of trinitrotoluene.

References Cited in the file of this patent UNITED STATES PATENTS 857,580 Bowen June 25, 1907 2,344,840 Watt Mar. 21, 1944 2,369,517 Bagley Feb. 13, 1945 FOREIGN PATENTS 22,030 Great Britain 1910 

1. A CAST COMPOSITION CONSISTING ESSENTIALLY OF AT LEAST 18 PARTS BY WEIGHT OF POWDERED ALUMINUM, A MINOR PORTION VARYING FROM 1/2 TO 4 PARTS BY WEIGHT OF A DESICCANT SELECTED FROM THE GROUP CONSISTING OF ANHYDROUS CALCIUM CHLORIDE, MAGNESIUM NITRATE, AND MAGNESIUM PERCHLORATE, AND AT LEAST 80 PARTS BY WEIGHT OF AN EXPLOSIVE CONTAINING AT LEAST 40 PARTS BY WEIGHT OF TRINITROTOLUENE. 